The invention generally relates to the composition of biocompatible materials and their application to body tissue to affect desired therapeutic results.
There are many therapeutic indications today that pose problems in terms of technique, cost efficiency, or efficacy, or combinations thereof.
For example, following an interventional procedure, such as angioplasty or stent placement, a 5 Fr to 8 Fr arteriotomy remains. Typically, the bleeding from the arteriotomy is controlled through pressure applied by hand, by sandbag, or by C-clamp for at least 30 minutes. While pressure will ultimately achieve hemostasis, the excessive use and cost of health care personnel is incongruent with managed care goals.
Various alternative methods for sealing a vascular puncture site have been tried. For example, collagen plugs have been used to occlude the puncture orifice. The collagen plugs are intended to activate platelets and accelerate the natural healing process. Holding the collagen seals in place using an anchor located inside the artery has also been tried. Still, patient immobilization is required until clot formation stabilizes the site. Other problems, such as distal embolization of the collagen, rebleeding, and the need for external pressure to achieve hemostatis, also persist.
As another example, devices that surgically suture the puncture site percutaneously have also been used. The devices require the practice of fine surgical skills to place needles at a precise distance from the edges of the puncture orifice and to form an array of suture knots, which are tightened and pushed from the skin surface to the artery wall with a knot pusher, resulting in puncture edge apposition.
There remains a need for fast and straightforward mechanical and chemical systems and methods to close vascular puncture sites and to accelerate the patient""s return to ambulatory status without pain and prolonged immobilization.
There also remains a demand for biomaterials that improve the technique, cost efficiency, and efficacy of these and other therapeutic indications.
The invention provides systems, methods, and compositions for achieving closure of vascular puncture sites. The systems and methods form a vascular closure composition by mixing together a first component, a second component, and a buffer material. The first component includes electrophilic polymer material having a functionality of at least three. The second component includes a nucleophilic material that, when mixed with the first component within a reaction pH range of between 7 to 9, cross-links with the first component to form a non-liquid, three-dimensional barrier. The buffer material has a pH within the reaction pH range. The systems and methods apply the composition to seal a vascular puncture site.
In a preferred embodiment, the first component comprises poly(ethylene glycol) having a molecular weight between 9,000 and 12,000. In a most preferred embodiment, the poly(ethylene glycol) has a molecular weight of 10,500xc2x11500. In these preferred embodiments, the second component comprises human serum albumin at a concentration of about 25% or less, and the buffer material includes tris-hydroxymethylaminomethane. The buffer material can also include sodium carbonate anhydrous. In a preferred embodiment, the second component, when mixed with the buffer material, and prior to mixing with the first component, has a pH of between 8.3 and 8.5.
Compositions that embody features of the invention are successful in sealing femoral puncture sites in less than 40 seconds.
Features and advantages of the inventions are set forth in the following Description and Drawings, as well as in the appended claims.